A: Infrared Absorption á197Kñ.

B: Ultraviolet Absorption 1á197Uñ—

C: Ultraviolet Absorption 2á197Uñ—

Standard copper solution— Dissolve 1000mg of copper wire in 6mLof nitric acid in a 1Lvolumetric flask.Add 8mLof hydrochloric acid,dilute with water to volume,and mix.Dilute this solution quantitatively and stepwise with water to obtain a Standard copper solutionhaving a known concentration of 0.6µg per mL.

Test solution— Transfer 2g of Meclofenamate Sodium,accurately weighed,to a 100-mLvolumetric flask,and add 1drop of ammonium hydroxide.Dissolve in water,dilute with water to volume,and mix.

Procedure— Concomitantly determine the absorbances of the Standard copper solutionand the Test solutionat the copper emission line at about 325nm,with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering á851ñ)equipped with a copper hollow-cathode lamp,using water as the blank.Adjust the operating conditions to obtain about 70%full-scale detector response with the Standard copper solution.The detector response obtained with the Test solutionis not greater than that obtained with the Standard copper solution(0.003%).

Standard solutions— Dissolve an accurately weighed quantity of USP Meclofenamate Sodium RSin methanol to obtain a solution containing 20mg per mL(Standard solution A).Dilute 1.0mLof Standard solution Awith sufficient methanol to obtain 200mLof solution (Standard solution B).

Test solution— Dissolve 200mg of Meclofenamate Sodium in 10.0mLof methanol.

Procedure— Apply 10-µLportions of Standard solution A,Standard solution B,and the Test solutionto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of methylene chloride,methyl ethyl ketone,and glacial acetic acid (50:48:2)until the solvent front has moved about eight-tenths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Examine the plate under short-wavelength UVlight:the chromatograms show a principal spot at about the same RFvalue,and any secondary spot,if present in the chromatogram from the Test solutionis not more intense than the principal spot obtained from Standard solution B(0.5%).